Inhibition of arachidonic acid metabolism and pro-inflammatory cytokine production by Bruguiera gymnorrhiza leaf

Bruguiera gymnorrhiza is a mangrove plant of the family Rhizophoraceae. The roots and leaves of the plant have traditionally been used for treating burns and mild inflammatory lesions. In the present study an attempt was made to evaluate the anti-inflammatory activity of the Bruguiera gymnorrhiza leaves. The methanolic fraction of Bruguiera gymnorrhiza leaves (BRG) was evaluated using different in vitro and in vivo models to evaluate the anti-inflammatory properties and also to obtain an insight on the probable mechanism of such activity. The leaf extract produced significant inhibition of both carrageenan induced rat paw oedema and acetic Acid induced peritoneal capillary permeability. The above observations were further supported by our findings from in vitro experimental models, where the plant extract produced significant inhibition of both cyclooxygenase (COX) and lipoxygenase (LOX) enzymes. Moreover, BRG inhibited the production of proinflammatory cytokines (TNF-alpha, IL-6 and IL-1 beta) in lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells (PBMCs) in a dose dependent manner. It was also found to possess significant free radical (DPPH, superoxide and oxygen radical) scavenging activity. From the results obtained from the various in vitro and in vivo test models, it may be concluded that the methanolic extract of Bruguiera gymnorrhiza leaves display significant anti-inflammatory properties, probably mediated through blockade of both COX - LOX pathway, coupled with scavenging effect on free radicals.